If you installed Windows 8.1 Update from the MSDN download provided by Microsoft last week, you didn't get the same set of patches that are currently being distributed on Windows Update/Microsoft Update. Many people who installed Win 8.1 Update from the MSDN download last week are complaining that they're being offered a new patch, KB 2934018, when looking in the April Black Tuesday patch list in Windows Update. Moreover, one of the patches in the MSDN download, KB 2949621-v2, doesn't exist on the Windows Update site.

Apparently, Microsoft swapped KB 2949621-v2 in last week's MSDN download package for the newer KB 2934018 and didn't tell anybody. The result is confusing, at best, for anyone who's been trying to reconcile their MSDN version of Windows 8.1 Update with the version everyone else is currently receiving. It's also confusing because people who installed Windows 8.1 Update last week are now being prompted by Windows Update to install Windows 8.1 Update again.

Here are the patches in the 32-bit Windows 8.1 Update as posted on MSDN (listed in the order in which they're supposed to be installed):

Windows8.1-KB2919442-x86.msu

Windows8.1-KB2919355-x86.msu

Windows8.1-KB2932046-x86.msu

Windows8.1-KB2937592-x86.msu

Windows8.1-KB2938439-x86.msu

Windows8.1-KB2949621-v2-x86.msu

Here are the patches currently being offered in Windows Update/Microsoft Update:

Windows8.1-KB2919442-x86.msu

Windows8.1-KB2919355-x86.msu

Windows8.1-KB2932046-x86.msu

Windows8.1-KB2937592-x86.msu

Windows8.1-KB2938439-x86.msu

Windows8.1-KB2934018-x86.msu

The 64-bit patches have similar names, ending in -x64.

The current MSDN download has not been changed -- it still has KB2949621-v2.

As a result, if you've already installed Windows 8.1 Update from the MSDN bits, venturing to Windows Update right now may bring a notice that you should install KB 2919355 (which is all of Windows 8.1 Update), or possibly KB 2934018 (the missing patch). In either case, you should go ahead and install the offered update.